Re: [PATCH 0/3] Convert clk-fixed into module platform driver
From: Stephen Boyd
Date: Wed Jun 15 2016 - 20:27:35 EST
On 06/15, Ricardo Ribalda Delgado wrote:
> Hi Stephen
>
> Assume this device tree overlay:
>
>
> &bus0{
>
> axi_clk: axi_clk {
> compatible = "fixed-clock";
> #clock-cells = <0x0>;
> clock-frequency = <125000000>;
> };
>
> iic_0: iic {
> #address-cells = <1>;
> #size-cells = <1>;
> compatible = "xlnx,xps-iic-2.00.a";
> reg = < 0x00030000 0x10000 >;
> interrupt-parent = <&xps_intc_0>;
> interrupts = < 2 2 >;
> clocks = <&axi_clk>;
> } ;
>
> }
>
> Which is basically a new i2c master and a fixed clock definition.
>
> The fixed clock driver will only be probed to the driver at arch
> initialization, when of_clk_init is called. The device overlay can be
> added at any point, usually after arch init. Which will result in ii_0
> failing to probe, because it is missing its clock.
>
> This changeset allows fixed clocks to be added after of_clk_init is
> called, by converting the driver into a platform driver.
>
Ok, so this is about supporting clks in overlays. I2C only comes
into the picture here because it's a consumer and happens to also
be on the same overlay.
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